Advancements in biotechnology and medical science require the analysis of ever-increasing numbers of various biological samples. Many biological samples must be stored at below-freezing temperatures in order to preserve them for future reference, analysis, or use. For example, DNA, RNA, cells and protein samples, as well as the reagents necessary for conducting various analyses of these samples, must be stored at ultra-cold temperatures to prevent degradation that would interfere with reliable analyses of the biological products.
Storage below −80° C. is generally required for successful preservation of biomolecules, cells, and tissue (morphology and viability) for extended periods of time. However, shelf life and the ability to recover living cells are dramatically improved at about −196° C. (−196° C. being the boiling point of liquid nitrogen). The National Institute of Standards and Technology has suggested that the term cryogenics be applied to all temperatures below −150° C. (−238° F. or 123° above absolute zero on the Kelvin scale). Some scientists regard the normal boiling point of oxygen (−183° C. or −297° F.), as the upper limit. The term ultra low temperature is probably not officially recognized by any standards body. However, it is generally agreed that a freezer refers to a storage device that operates from about −5° C. to −20° C., an ultra low operates from about −50° C. to about −90° C., and a cryogenic freezer operates from about −140° C. to −196° C.
There are many problems associated with placement and retrieval of samples from ordinary laboratory freezer compartments. For instance, in an ordinary freezer compartment, containers of samples must be stored in front of and on top of each other to maximize use of the available space. Even if the containers are of standard sizes, and therefore easily stackable and even if a positional inventory of the samples is kept, it is still necessary to shuffle the containers around manually in order to retrieve a desired container. This is problematic because it requires keeping the freezer door open for possibly extended periods of time. Keeping the freezer door open causes the interior temperature of the freezer compartment to rise temporarily, which can cause thawing of samples housed near the door of the freezer. Once the freezer is closed and the temperature decreases, the samples refreeze. This repeated freezing and thawing can cause more rapid degradation of samples. Keeping the freezer door open also allows frost to build up in the freezer compartment. With repeated openings of the door, the frost eventually can freeze containers to the bottom of the freezer compartment or to each other. As a result, the door must be kept open longer in order to break containers out of the frost, which only exacerbates the problem.
The increasing need for high quality bio-repositories in hospitals, research institutions, and pharmaceutical clinical research laboratories provides a market for automated ultra-cold storage devices that will improve sample quality, organize storage, provide rapid access to all specimens, and maintain electronic records of all specimens stored within the container.
U.S. Pat. No. 5,921,102 to Vago, herein incorporated by reference, utilizes a storage apparatus particularly with automatic insertion and retrieval. Drawbacks of the Vago approach, but not limited thereto, are that it fails to provide the climate control associated with the freezer and the various interchanging devices, and other features and aspects.
There is therefore a need in the art for an automated cold storage apparatus, and related method thereof, that can provide, among other things a more organized storage and retrieval apparatus, less accumulation of moisture and frost within the cold storage compartment, less temperature fluctuation from sample withdrawal, and rapid random access to all specimens.